Fisheries experts will reduce salmon to make them bigger
Written by Muskegon Chronicle   
Wednesday, 05 October 2005 14:08

Having spent numerous summers working on a Lake Michigan charter fishing boat, Drew Morris has experienced the best and worst of the lake's prized salmon fishery. Morris was a participant in the breathtaking fishing of the 1970s and '80s, when anglers routinely hauled in 30-pound chinook salmon that pulled like pitbulls on a chew toy.

 

And he saw the salmon fishery crash in the late 1980s, when a mysterious kidney ailment decimated chinook and thousands of dead fish washed up on beaches.

 

"The salmon are way smaller than they have been in the past," Morris said. "I used to catch a bunch of salmon over 30 pounds but I didn't get any that big this year."

Now Morris, along with every other Lake Michigan angler, is about to witness an unprecedented biological experiment carried out in the lake.

Government fish biologists in Michigan, Wisconsin, Illinois and Indiana are about to launch an effort to simultaneously bolster the health of the lake's two top predators, chinook and lake trout, by slashing salmon stocking 25 percent in 2006.

Biologists said there are currently too many salmon in the lake and too few alewife, the fish that salmon and lake trout eat. As a result, chinook are getting smaller, according to state data.

Trying to support healthy populations of chinook and lake trout is a risky proposition because the fish often compete for the same food.

Biologists hope that stocking fewer chinook results in larger, healthier salmon and more lake trout. But if the plan backfires, chinook or lake trout populations -- possibly both -- could suffer, according to biologists familiar with the plan.

"We're trying to walk a fine line here and we could fall off in either direction," said Jim Dexter, Lake Michigan basin coordinator for the Michigan Department of Natural Resources. "This is a very important time in the management of a very perturbed system (Lake Michigan); we're dealing with so many exotic species it makes management of the fishery very difficult."

At the heart of the issue is a booming chinook population and dwindling alewife numbers. The alewife population has plummeted in recent years, a problem some scientists blame on zebra mussels.

Zebra mussels are suspected of causing a decline in the number of diporeia, tiny shrimp-like creatures in the lake that alewife and other fish eat. The result: Alewife and salmon are going hungry and shrinking.

Lake trout, which are native to Lake Michigan, have not reproduced naturally in large numbers for the past few decades. Though lake trout eat alewife, they are susceptible to a disease carried by the small, silver fish, according to government biologists.

Left unchecked, scientists fear Lake Michigan's salmon fishery could become a mirror image of Lake Huron, where alewife have all but disappeared and the chinook fishery is struggling. Lake trout, on the other hand, are increasing in Lake Huron.

Biologists plan to reduce chinook stocking in Lake Michigan to 3.2 million fish in 2006, down from 4.3 million this year. They said there simply aren't enough alewife to support the existing chinook population.

Stocking fewer fish does not necessarily mean anglers will catch fewer salmon. But Michigan anglers could feel more of a pinch because the state stocks 70 percent of the chinook in Lake Michigan.

Government biologists reduced chinook stocking in Lake Michigan by 27 percent in 1999 and the fishing actually improved, according to state data.

Since 1967, when the state planted chinook to control an explosion of alewife, government agencies that oversee Lake Michigan have focused almost exclusively on propping up the salmon fishery, Dexter said.

Striking a balance between chinook -- which are known affectionately among anglers as "kings" -- and lake trout, often derided as "greaseballs," will be difficult in a lake that is dominated by exotic species, said Henry Quinlan, a fishery biologist at the U.S. Fish and Wildlife Service office in Ashland, Wis.

"In Lake Michigan and Lake Huron, the ecosystem is now based almost entirely on exotic species and the ecosystem stability is very fragile," Quinlan said.

Some anglers have argued the states should reduce chinook stocking in Lake Michigan by 50 percent or more to fatten up salmon.

But American Indians, who favor native lake trout over introduced species such as salmon, are opposed to reducing the number of chinook planted in Lake Michigan. The reason: fewer chinook could mean more alewife, and alewife cause problems for lake trout and perch.

"We think the number one impediment to native species recovery in the lake is alewife," said Tom Gorenflo, director of the intertribal fisheries program for Chippewa Ottawa Resource Authority in Sault Saint Marie. "In Lake Michigan, we're concerned that chinook stocking cuts without an increase in other species may give alewife a boost, which we don't want to happen."

Gorenflo said he will express the tribes' concerns about the reduced chinook stocking plan when the Great Lakes Fishery Commission's Lake Michigan Committee holds its stocking conference later this month. Gorenflo said he wants the states to strike a balance between chinook and lake trout populations in Lake Michigan.

Some anglers said that's not possible because lake trout and salmon compete for the same food.

"You can't have everything," said Denny Grinold, who operates a charter fishing boat out of Grand Haven. "We don't have lake trout to speak of. If we crash the forage base for chinook in Lake Michigan (by wiping out alewife) we'll have nothing to catch."

Goals established by the Great Lakes Fishery Commission, a collaborative of the eight states and two Canadian provinces around the lakes, suggested chinook account for 50 percent of the trout and salmon harvest, by weight, in Lake Michigan. Chinook now account for nearly 80 percent of the salmon and trout harvest, said Grinold, who chairs a citizens advisory panel that monitors Lake Michigan fishery issues.

Gorenflo said the states surrounding Lake Michigan have fallen fall short of the lake trout stocking levels recommended in a 1985 plan to rehabilitate the struggling species.

"That plan called for a certain amount of lake trout to be stocked per acre of suitable habitat and we're about two million fish short," Gorenflo said. "You can't have it both ways. You can't have this world class chinook fishery and lake trout rehabilitation."

Dexter said it's worth a try.

"All the agencies are going to try to balance predator and prey species in a way that there is enough prey to feed all the predators without affecting the native species," Dexter said. "I'll be the first to tell you that it might not be possible to do this, but the states are not wrong for trying this."

 
You need to login or register to post comments.
Discuss...